[jQuery] tablesorter, sort values in anchor as numerics

I have data that looks like that

<a href='myURL/myapp?name=myname&param1=val'>23</a>
<a href='myURL/myapp?name=hisname&param1=val1'>9</a>

I need it to be sorted numericaly by values between ></a>. How do I
do that?